Thiadiazolylimidazolidinone herbicides

ABSTRACT

This invention discloses the compound 1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one and its use as a herbicide.

This application is a division of copending application Ser. No.441,611, filed Feb. 11, 1974, now Pat. No. 3,932,438 which is acontinuation in part of application Ser. No. 375,203, filed June 29,1973, now abandoned.

This invention relates to a new composition of matter and morespecifically relates to the compound1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one.The compound of the present invention has the following structuralformula: ##EQU1##

The compound of the present invention has unexpected utility as aherbicide.

The manner in which the compound of this invention can be preparedreadily is illustrated in the following examples.

Example 1 Preparation of 5-Trifluoromethyl-1,3,4-thiadiazol-2-ylIsocyanate Dimer

A saturated solution of phosgene in ethyl acetate (100 ml) was chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-trifluoromethyl-2-amino-1,3,4-thiadiazole (45 grams) inethyl acetate (300 ml) was added to the reaction vessel and theresulting mixture was stirred for a period of about 16 hours resultingin the formation of precipitate. The reaction mixture was then purgedwith nitrogen gas to remove unreacted phosgene. The purged mixture wasfiltered to recover 48 grams of a white solid. This solid wasrecrystallized from dimethyl formamide to yield the desired product5-trifluoromethyl-1,3,4-thiadiazol-2-yl isocyanate dimer.

Example 2 Preparation of the Dimethyl Acetal of2-[1-methyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde

A mixture of 5-trifluoromethyl-1,3,4-thiadiazol-2-yl isocyanate dimer(9.5 grams), the dimethyl acetal of 2-methylaminoacetaldehyde (5.8grams) and benzene (60 ml) are charged into a glass reaction vesselequipped with a mechanical stirrer and reflux condenser. The reactionmixture is heated at reflux for a period of about 15 minutes. After thistime the mixture is stripped of benzene under reduced pressure to yielda solid product as the residue. This product was recrystallized fromheptane to yield the desired product the dimethyl acetal of2-[1-methyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehydehaving a melting point of 101° to 102°C.

Example 3 Preparation of1-(5-Trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-methyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde(15 grams), water (400 ml) and hydrochloric acid (4 ml) were chargedinto a glass reaction vessel equipped with a mechanical stirrer,thermometer and reflux condenser. The reaction mixture was heated atreflux for a period of about 15 minutes. The reaction mixture was thenfiltered while hot and the filtrate was cooled resulting in theformation of a precipitate. The precipitate was recovered by filtration,was dried and was recrystallized from an ethyl acetate-hexane mixture toyield the desired product1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-onehaving a melting point of 136° to 138°C.

For practical use as a herbicide the compound of this invention isgenerally incorporated into herbicidal compositions which comprise aninert carrier and a herbicidally toxic amount of the compound. Suchherbicidal compositions, which can also be called formulations, enablethe active compound to be applied conveniently to the site of the weedinfestation in any desired quantity. These compositions can be solidssuch as dusts, granules, or wettable powders; or they can be liquidssuch as solutions, aerosols, or emulsifiable concentrates.

For example, dusts can be prepared by grinding and blending the activecompound with a solid inert carrier such as the talcs, clays, silicas,pyrophyllite, and the like. Granular formulations can be prepared byimpregnating the compound, usually dissolved in a suitable solvent, ontoand into granulated carriers such as the attapulgites or thevermiculites, usually of a particle size range of from about 0.3 to 1.5mm. Wettable powders, which can be dispersed in water or oil to anydesired concentration of the active compound, can be prepared byincorporating wetting agents into concentrated dust compositions.

In some cases the active compound is sufficiently soluble in commonorganic solvents such as kerosene or xylene so that it can be useddirectly as a solution in these solvents. Frequently, solutions ofherbicides can be dispersed under superatmospheric pressure as aerosols.However, preferred liquid herbicidal compositions are emulsifiableconcentrates, which comprise the active compound according to thisinvention and as the inert carrier, a solvent and an emulsifier. Suchemulsifiable concentrates can be extended with water and/or oil to anydesired concentration of active compound for application as sprays tothe site of the weed infestation. The emulsifiers most commonly used inthese concentrates are nonionic or mixtures of nonionic with anionicsurface-active agents. With the use of some emulsifier systems aninverted emulsion (water in oil) can be prepared for direct applicationto weed infestations.

A typical herbicidal composition according to this invention isillustrated by the following example, in which the quantities are inparts by weight.

Example 4

    Preparation of a Dust                                                         Product of Example 3    10                                                    Powdered Talc           90                                                

The above ingredients are mixed in a mechanical grinder-blender and areground until a homogeneous, free-flowing dust of the desired particlesize is obtained. This dust is suitable for direct application to thesite of the weed infestation.

The compound of this invention can be applied as a herbicide in anymanner recognized by the art. One method for the control of weedscomprises contacting the locus of said weeds with a herbicidalcomposition comprising an inert carrier and as an essential activeingredient, in a quantity which is herbicidally toxic to said weeds, thecompound of the present invention. The concentration of the new compoundof this invention in the herbicidal compositions will vary greatly withthe type of formulation and the purpose for which it is designed, butgenerally the herbicidal compositions will comprise from about 0.05 toabout 95 per cent by weight of the active compound of this invention. Ina preferred embodiment of this invention, the herbicidal compositionswill comprise from about 5 to about 75 per cent by weight of the activecompound. The compositions can also comprise such additional substancesas other pesticides, such as insecticides, nematocides, fungicides, andthe like; stabilizers, spreaders, deactivators, adhesives, stickers,fertilizers, activators, synergists, and the like.

The compound of the present invention is also useful when combined withother herbicides and/or defoliants, dessicants, growth inhibitors, andthe like in the herbicidal compositions heretofore described. Theseother materials can comprise from about 5% to about 95% of the activeingredients in the herbicidal compositions. Use of combinations of theseother herbicides and/or defoliants, dessicants, etc. with the compoundof the present invention provide herbicidal compositions which are moreeffective in controlling weeds and often provide results unattainablewith separate compositions of the individual herbicides. The otherherbicides, defoliants, dessicants and plant growth inhibitors, withwhich the compound of this invention can be used in the herbicidalcompositions to control weeds, can include chlorophenoxy herbicides suchas 2,4-D, 2,4,5-T, MCPA, MCPB, 4(2,4-DB), 2,4-DEB, 4-CPB, 4-CPA, 4-CPP,2,4,5-TB, 2,4,5-TES, 3,4-DA, silvex and the like; carbamate herbicidessuch as IPC, CIPC, swep, barban, BCPC, CEPC, CPPC, and the like;thiocarbamate and dithiocarbamate herbicides such as CDEC, methamsodium, EPTC, diallate, PEBC, perbulate, vernolate and the like;substituted urea herbicides such as norea, siduron, dichloral urea,chloroxuron, cycluron, fenuron, monuron, monuron TCA, diuron, linuron,monolinuron, neburon, buturon, trimeturon and the like; symmetricaltriazine herbicides such as simazine, chlorazine, atraone, desmetryne,norazine, ipazine, prometryn, atrazine, trietazine, simetone, prometone,propazine, ametryne, and the like; chloroacetamide herbicides such asalpha-chloro-N, N-dimethylacetamide, CDEA, CDAA,alpha-chloro-N-isopropylacetamide, 2-chloro-N-isopropylacetanilide,4-(chloroacetyl)morpholine, 1-(chloroacetyl)piperidine, and the like;chlorinated aliphatic acid herbicides such as TCA, dalapon,2,3-dichloropropionic acid, 2,2,3-TPA and the like; chlorinated benzoicacid and phenylacetic acid herbicides such as 2,3,6-TBA, 2,3,5,6-TBA,dicamba, tricamba, amiben, fenac, PBA,2-methoxy-3,6-dichlorophenylacetic acid,3-methoxy-2,6-dichlorophenylacetic acid,2-methoxy-3,5,6-trichlorophenylacetic acid, 2,4-dichloro-3-nitrobenzoicacid and the like; and such compounds as aminotriazole, maleichydrazide, phenyl mercuric acetate, endothal, biuret, technicalchlordane, dimethyl 2,3,5,6-tetrachloroterephthalate, diquat, erbon,DNC, DNBP, dichlobenil, DPA, diphenamid, dipropalin, trifluralin, solan,dicryl, merphos, DMPA, DSMA, MSMA, potassium azide, acrolein, benefin,bensulide, AMS, bromacil,2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione,bromoxynil, cacodylic acid, CMA, CPMF, cypromid, DCB, DCPA, dichlone,diphenatril, DMTT, DNAP, EBEP, FXD, HCA, ioxynil, IPX, isocil, potassiumcyanate, MAA, MAMA, MCPES, MCPP, MH, molinate, NPA, OCH, paraquat, PCP,picloram, DPA, PCA, pyrichlor, sesone, terbacil, terbutol, TCBA,brominil, CP-50144, H-176-1, H-732, N-2901, planavin, sodiumtetraborate, calcium cyanamid, DEF, ethyl xanthogen disulfide, sindone,sindone B, propanil and the like.

Such herbicides can also be used in the methods and compositions of thisinvention in the form of their salts, esters, amides, and otherderivatives whenever applicable to the particular parent compounds.

Weeds are undesirable plants growing where they are not wanted, havingno economic value, and interfering with the production of cultivatedcrops, with the growing of ornamental plants, or with the welfare oflivestock. Many types of weeds are known, including annuals such aspigweed, lambsquarters, foxtail, crabgrass, wild mustard, fieldpennycress, ryegrass, goose-grass, chickweed, wild oats, velvetleaf,purslane, barnyard grass, smartweed, knotweed, cocklebur, wildbuckwheat, kochia, medic, corn cockle, ragweed, sowthistle, coffeeweed,croton, cuphea, dodder, fumitory, groundsel, hemp nettle, knawel,spurge, spurry, emex, jungle rice, pondweed, dog fennel, carpetweed,morning glory, bedstraw, ducksalad, naiad, cheatgrass, fall panicum,jimsonweed, witchgrass, switchgrass, watergrass, teaweed, wild turnipand sprangletop; biennials such as wild carrot, matricaria, wild barley,campion, chamomile, burdock, mullein, roundleaved mallow, bull thistle,hounds-tongue, moth mullein and purple star thistle; or perennials suchas white cockle, perennial ryegrass, quackgrass, Johnson grass, Canadathistle, hedge bindweed, Bermuda grass, sheep sorrel, curly dock,nutgrass, field chickweed, dandelion, campanula, field bindweed, Russianknapweed, mesquite, toadflax, yarrow, aster, gromwell, horsetail,ironweed, sesbania, bulrush, cattail, winter-cress, horsenettle,nutsedge, milkweed and sicklepod.

Similarly, such weeds can be classified as broadleaf or grassy weeds. Itis economically desirable to control the growth of such weeds withoutdamaging beneficial plants or livestock.

The new compound of this invention is particularly valuable for weedcontrol because it is toxic to many species and groups of weeds while itis relatively nontoxic to many beneficial plants. The exact amount ofthe compound required will depend on a variety of factors, including thehardiness of the particular weed species, weather, type of soil, methodof application, the kind of beneficial plants in the same area, and thelike. Thus, while the application of up to only about one or two ouncesof the active compound per acre may be sufficient for good control of alight infestation of weeds growing under adverse conditions, theapplication of ten pounds or more of active compound per acre may berequired for good control of a dense infestation of hardy perennialweeds growing under favorable conditions.

The herbicidal toxicity of the new compound of this invention can beillustrated by many of the established testing techniques known to theart, such as per- and post-emergence testing.

The herbicidal activity of the compound of this invention wasdemonstrated by experiments carried out for the pre-emergence control ofa variety of weeds. In these experiments small plastic greenhouse potsfilled with dry soil were seeded with the various weed seeds.Twenty-four hours or less after seeding the pots were sprayed with wateruntil the soil was wet and the test compound formulated as a solution inan inert solvent was sprayed at the indicated concentrations on thesurface of the soil.

After spraying, the soil containers were placed in the greenhouse andprovided with supplementary heat as required and daily or more frequentwatering. The plants were maintained under these conditions for a periodof 27 days, at which time the condition of the plants and the degree ofinjury to the plants was rated on a scale of from 0 to 10, as follows: 0= no injury, 1,2 = slight injury, 3,4 = moderate injury, 5,6 =moderately severe injury, 7,8,9 = severe injury and 10 = death. Theeffectiveness of the compound is demonstrated by the following data inTable I.

                  TABLE I                                                         ______________________________________                                                       Injury Rating                                                                 Rate in lbs./acre                                              WEED SPECIES     5        2        1                                          ______________________________________                                        Yellow nutsedge   9        9       10                                         Wild Oats        10       10       10                                         Jimsonweed       10       10       10                                         Velvetleaf       10       10       10                                         Johnsongrass     10       10       10                                         Pigweed          10       10       10                                         Mustard          10       10       10                                         Yellow foxtail   10       10       10                                         Barnyardgrass    10       10       10                                         Crabgrass        10        5        4                                         Cheatgrass       10       10       10                                         Morning glory    10       10       10                                         ______________________________________                                    

The herbicidal activity of the compound of this invention was alsodemonstrated by the experiments carried out for the post-emergencecontrol of a variety of weeds. In these experiments the compound wasformulated as a solution in an inert solvent and sprayed at theindicated dosage on the foliage of the weeds that have attained aprescribed size. After spraying, the plants were placed in a greenhouseand watered daily or more frequently. Water was not applied to thefoliage of the treated plants. The severity of the injury was determined17 days after treatment and was rated on the scale of from 0 to 10heretofore described. The effectiveness of the compound is demonstratedby the data in Table II.

                  TABLE II                                                        ______________________________________                                                       Injury Rating                                                                 Rate in lbs./acre                                              WEED SPECIES     5        2        1                                          ______________________________________                                        Yellow nutsedge  10       10       10                                         Wild oats        10       10       10                                         Jimsonweed       10       10       10                                         Pigweed          10       10       10                                         Johnsongrass     10       10       10                                         Velvetleaf       10       10       10                                         Mustard          10       10       10                                         Yellow foxtail   10       10       10                                         Barnyardgrass    10       10       10                                         Crabgrass        10       10       10                                         Cheatgrass       10       10       10                                         Morning glory    10       10       10                                         ______________________________________                                    

I claim:
 1. A herbicidal composition comprising an inert carrier and asan essential active ingredient, in a quantity toxic to weeds, thecompound1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one.2. A method of controlling weeds which comprises contacting said weedswith a herbicidal composition of claim 1.